1. Technical Field
The present invention relates to a voltage detection device, a voltage detection method, an abnormality determination device, an abnormality determination method and a battery pack system.
2. Related Art
A battery pack in which battery stacks, each of which has a plurality of battery cells connected in series, are connected in series has been used as a power supply of an electric vehicle and a hybrid electric vehicle, for example. The battery pack is connected with a monitoring device configured to monitor the battery pack. The monitoring device is configured to operate as a voltage detection device configured to detect a voltage of the battery pack and an abnormality determination device configured to determine whether an abnormality has occurred in the battery pack or the monitoring device.
As the abnormality to occur in the battery pack, a so-called open abnormality has been known in which a connection member configured to connect two adjacent battery stacks is disconnected and an open state is thus made between terminals of the two battery stacks. In the abnormality detection device of the related art, a Zener diode is provided on a bypath route configured to connect both ends of the connection member so as to detect the open abnormality between the battery stacks (for example, refer to Patent Document 1 (JP-A-2014-183671)).
Also, as a device configured to determine whether an abnormality has occurred in an electric pathway of the voltage detection device, a device having two voltage detection circuits has been known (for example, refer to Patent Document 2 (JP-A-2008-79415)). In this device, it is determined whether an abnormality has occurred in the electric pathway, based on voltages detected by the two voltage detection circuits.